The present invention relates to a circuit for a motor vehicle, in particular for actuating a lighting device, the circuit having a first light source and a second light source connected in parallel, the first light source being assigned a first current sink and the second light source being assigned a second current sink, and the circuit being assigned a measuring means.
Such circuits for motor vehicles are generally known. For example, the German laid-open specification DE 101 15 388 A1 discloses a drive circuit for an LED array, the drive circuit comprising at least one first LED strand and at least one second LED strand, a switch being arranged in series with each LED strand and each LED strand having a supply connection, a control loop being designed in such a manner that it drives the first switch of the first LED strand so as to achieve a constant mean value of the current flowing through the first LED strand, the control loop also being designed to drive the switches of the further LED strands. The drive circuit also comprises a total current detection apparatus which can be used to determine the sum of currents through at least two LED strands.
The disadvantage of this is that a distinction is made between a so-called master LED strand and further LED strands, with the result that, in the event of a functional disturbance in the so-called master LED strand, the circuit fails, which has an adverse affect on the functional reliability of the circuit.
The object of the present invention is to provide a drive circuit for a motor vehicle, in particular for actuating a lighting device, in which lighting failures or failures of the light source or other fault states are detected and a flexible response is given to such faults. Furthermore, the intention is to minimize the thermal power loss.